Potential High Energy Density Compounds Research Articles

Design and properties of a new family of wing-like and propeller-like multi-tetrazole molecules as potential high-energy density compounds.

Density functional theory (DFT) methods were employed to design a new family of wing-like and propeller-like multi-tetrazole molecules based on the combination of N-center multi-tetrazole and various energetic groups. The optimized geometry, electronic properties, and thermodynamics were calculated for investigating the molecular stability and chemical reactivity. Their energetic parameters including density, heats of formation, detonation properties, and impact sensitivity were extensively evaluated, and the effects of energetic groups were investigated as well. These newly designed wing-like and propeller-like multi-tetrazole molecules exhibit acceptable oxygen balance, moderate impact sensitivities, high density, excellent heats of formation, and good detonation performance. Especially, B3, B4, B5, and B6 are very helpful for enhancing their detonation performance (D ≥ 9500m·s-1, P ≥ 41 GPa) are promising candidates for new environmentally friendly HEDMs.

New Potential High Energy Density Compounds: 7-Amino-6-nitro-[1,2,5]oxadiazolo[3,4-b]pyridine-1-oxide Derivatives

New Potential High Energy Density Compounds: 7-Amino-6-nitro-[1,2,5]oxadiazolo[3,4-b]pyridine-1-oxide Derivatives

Computer-aided design and property prediction of novel insensitive high-energy heterocycle-substituted derivatives of cage NNNAHP

A series of new derivatives of cage 2,4,6,8,10,12,13,14,15-nanonitro-2,4,6,8,10,12,13,14, 15-nanoazaheptacyclo[5.5.1.13,11,15,9] pentadecane (NNNAHP) were designed by incorporating combination of heterocyclic and non-heterocyclic substituents and studied by using density functional theory. The results indicate that the -tetrazine and -N(NO2)2 are very beneficial structural fragments to increase their heat of formation. The introduction of different heterocyclic and non-heterocyclic groups can produce different effects on different properties: large densities (1.88-2.06gcm-3), high detonation velocities (8.17-9.83kms-1), excellent detonation pressures (30.55-46.02GPa), and outstanding heat of detonations (1169.80-1637.19calg-1). The analysis of bond dissociation energy values show that the N(cage)-NO2 is the weakest bond, and it may turn into a trigger bond during detonation. Almost all the derivatives are thermally more stable than the parent compound. All the substituted derivatives are insensitive as compared with the parent compound. According to excellent detonation properties, high thermal stability, and good insensitivity, 10 compounds may be chosen as potential high-energy density compounds.

Theoretical exploration about the thermal stability and detonation properties of nitro-substituted hypoxanthine

Nitro-substituted derivatives of hypoxanthine are designed by substituting the hydrogen atoms by nitro groups. The heats of formation (HOF) are calculated at the G3MP2 level to confirm the thermal stability. Also, the bond dissociation energy (BDE) accompanied by the bond order is calculated at the same level to explore kinetic stability. To evaluate the potential application as high-energy density materials, the explosive heat, the molecular density, the detonation pressure, and detonation velocity are estimated by using the Kamlet-Jacobs (K-J) equation. Furthermore, the molecular sensitivities are considered by calculating the character height (H50) and the amount of free space per molecule in the crystal lattice (ΔV). Based on our calculations, the trinitro-substituted hypoxanthine (C) is screened out as the potential high-energy density compounds for further study.

Computational insight into polynitromethyl- and polydifluoroaminomethyl-substituted energetic derivatives of 2,3-dihydro pyrazino [2,3-e] [1, 2, 3, 4] tetrazine.

A series of energetic polynitromethyl and polynitromethyl substituents were designed and then incorporated into 2,3-dihydro pyrazino [2,3-e] [1, 2, 3, 4] tetrazine molecule. The heat of formations, frontier molecular orbitals, electronic densities, electrostatic potentials, thermal stability, and impact sensitivity of the designed compounds were predicted by density functional theory. Most of the title compounds possess excellent comprehensive performance, that is, large densities (1.90 to 2.35gcm-3), high detonation velocities (9.00 to 13.02kms-1), and high detonation pressures (40.00 to 85.41GPa). Due to their good detonation properties, suitable thermal stability, and other properties, 10 compounds (A2, A3, A6, B3, B6, C6, D3, D6, E3, and E6) were screened as the potential high-energy density compounds. The results and the ideas of molecular design proposed in this work are expected to assist the experimental researchers in the synthesis of new fluorine- and oxygen-rich high-energy density compounds.

Designing and looking for novel low-sensitivity and high-energy cage derivatives based on the skeleton of nonanitro nonaaza pentadecane framework

We designed 12 novel cage-shaped high energy density compounds by incorporating –O– moiety and replacing up to two –NO2 groups at the different positions by –NH2 groups into the basic 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15 nonaazaheptacyclo [5.5.1.13, 11. 15, 9] pentadecane (NNNAHP) skeleton. Their geometrical structures, electronic structures, heats of formation, detonation properties, thermodynamic properties, thermal stability, impact sensitivity, and free spaces were studied by using density functional theory. The favorable substitution position is a very important factor to tune the detonation properties, thermal stability, and impact sensitivity of the designed compounds. The thermal stability of the designed compounds was analyzed based on the bond dissociation energy of the weakest bond among all the bonds in a compound. The impact sensitivity and free spaces of the designed compounds were compared with well-known cage high energy density compound CL-20. Due to large densities, excellent detonation performance, suitable thermal stability, and low sensitivity, 11 compounds were chosen as potential high energy density compounds having huge potential for their synthesis.

Structure design and property adjustment of new cage rich-nitrogen pentazolyltetraazacubanes as potential high energy density compounds

In this study, based on two attractive energetic compounds pentazole (PZ) and tetraazacubane (TAC), a new family of high energy and high nitrogen compounds pentazolyltetraazacubanes were designed. Then, a different number of NH2 or NO2 groups were introduced into the system to further adjust the property. The structures, properties, and the structure-property relationship of designed molecules were investigated theoretically. The results showed that all nine designed compounds have extremely high heat of formation (HOF, 1226-2734 kJ/mol), good density (1.73–1.88 g/cm3), high detonation velocity (8.30–9.35 km/s), high detonation pressure (29.8–39.7 GPa) and acceptable sensitivity (ΔV: 41-87 Å3). These properties could be effectively positive adjusted by replacing one or two PZ rings by NH2 or/and NO2 groups, especially for the energy and sensitivity performance, which were increased and decreased obviously, respectively. As a result, two designed pentazolyltetraazacubanes were predicted to have higher energy and lower sensitivity than the famous high energy compound in use 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, while two others have better combination property than 1,3,5-Trinitro-1,3,5-triazacyclohexane. In all, four new pentazolyltetraazacubanes with good combination performance were successfully designed by combining PZ with TAC, and the further property adjustment strategy of introducing a suitable amount of NH2/NO2 groups into the system. This work may help develop new cage energetic compounds.

Theoretical investigation of the structure, detonation properties, and stability of bicyclo[3.2.1]octane derivatives.

A series of nitro group and aza nitrogen atom derivatives, based on bicyclo[3.2.1]octane, were designed and studied by theoretical methods. The geometric structure calculations were performed at B3LYP/6-311G(d,p), B3P86/6-311G(d,p), B3LYP/6-31G(d), and B3PW91/6-31G(d,p) levels. The electrostatic potential analysis, heats of formation, densities, heats of sublimation, detonation performances, bond dissociation energies (BDEs), and impact sensitivities of the designed compounds were calculated by reasonable calculation methods to evaluate their comprehensive properties and establish the relationship between structure and performance. Results show that density and detonation properties always increase with the increasing number of nitro groups and aza nitrogen atoms. BDEs generally decrease with the increasing number of nitro groups. Except for BDEs of A9, B9, and D8, BDEs of all designed compounds are larger than 20 kcal mol-1 and meet the requirement for new high energy density compounds (HEDCs). Two theoretical prediction methods show all the designed compounds have an acceptable impact sensitivity. Detonation velocity and detonation pressure were predicted in the range of 5.24-9.59 km/s and 9.97-43.44 GPa, respectively. Eleven compounds have better detonation properties than HMX, and seven compounds meet the criteria for HEDCs. Taking thermal stability and impact sensitivity into consideration, four compounds (C9, E8, F8, and G7) may be considered as new potential HEDCs, and C9, E8, and F8 may have similar detonation properties to the famous CL-20. Graphical abstractFour new HEDCs with acceptable impact sensitivity (C9, E8 and F8 may have similar detonation properties to the famous CL-20).

Molecular design on a new family of azaoxaadamantane cage compounds as potential high-energy density compounds

A new family of azaoxaadamantane cage compounds were firstly designed by introducing the oxygen atom into hexanitrohexaazaoxaadmantane (HNHAA) to replace the N–NO2 group. Their properties including heats of formation (HOFs), detonation properties, strain energies, thermal stability, and sensitivity were extensively studied by using density functional theory. All of the title compounds exhibit surprisingly high density (ρ > 2.01 g/cm3) and excellent detonation properties (detonation velocity (D) > 9.29 km/s and detonation pressure (P) > 40.80 GPa). In particular, B (4,8,9,10-tetraazadioxaadamantane) and C (6,8,9,10-tetraazadioxaadamantane) have a remarkably high D and P values (9.70 km/s and 44.45 GPa, respectively), which are higher than that of HNHAA or CL-20. All of the title compound have higher thermal stability and lower sensitivity (h50 > 19.58 cm) compared with the parent compound HNHAA. Three triazatrioxaadamantane cage compounds, D (6,8,9-triazatrioxaadamantane), E (6,8,10-triazatrioxaadamantane), and F (8,9,10-triazatrioxaadamantane), are expected to be relatively insensitive explosives. All of the title compounds exhibit a combination of high denotation properties, good thermal stability, and low insensitivity.

High-nitrogen nitrotetrazole substituted tetrazole 3-N-oxides as potential high energy density compounds

In this work, two series of novel high-nitrogen tetrazole 3-N-oxides substituted by different nitrotetrazoles were designed, and their structure and properties were investigated by using the density functional theory (DFT) method. The results shown that though there are only one to two energetic substituents in the structure, because of the high nitrogen content, ideal oxygen balance, and the big conjugated structure, all eight designed compounds not only have high heat of formation (655.4–845.6 kJ/mol), high density (1.83–1.93 g/cm3), and high detonation performance (detonation velocity: 9.06–9.50 km/s; detonation pressure: 36.7–41.8 GPa), but also possess reduced impact sensitivity (23–98 cm). Fully analyzing the energy and sensitivity, A1 and A4 have higher energy and lower sensitivity than one famous high energy compound 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), and A3, B1, and B4 have comparable overall performance with HMX, showing that these five designed compounds may be considered as the potential high energy density compounds. In addition, the introduction of one extra nitro group into the tetrazole 3-N-oxide could not improve the combination property generally.

Theoretical Insight into the Structure, Energetic Property and Thermal Stability of C6N6H12 Cages

Recent theoretical studies have identified carbon-nitrogen cages are potentially stable high energy density materials. Two such C6N6H12 cages were proposed and investigated using the density functional theory comparison with two similar common cage compounds hexaazaisowurtzitane and cubane. The structure and energetic property were researched. Stability is approached in two ways: (1) stability of one isomer versus another based on the relative energy, (2) thermal stability determined by the bond breaking energies. Taking into consideration of the stability and detonation performance, two C6N6H12 cages may be candidate as potential high energy density compounds.

A Theoretical Investigation of Potential High Energy Density Compounds of Keto RDX Derivatives with -NO2 and -F Groups

A Theoretical Investigation of Potential High Energy Density Compounds of Keto RDX Derivatives with -NO2 and -F Groups

Design and theoretical study of 15 novel high energy density compounds.

In order to seek the potential high energy density compounds (HEDCs) with excellent performance and satisfactory safety, some combination rules are presented and 15 HEDCs are designed and sifted, and followed by the properties predicting. From the results, HEDC-3, HEDC-4, HEDC-9, HEDC-10, HEDC-11, HEDC-12, HEDC-13, and HEDC-14 have good comprehensive properties. They are furoxan, fused ring or cage-type compounds, whose frame is composed of some single ring by single (double or multi) point addition. Their densities are over 1.95gcm(-3), and detonation velocities are over 9500ms(-1). Their BDEs are over 85kJmol(-1), and the values of available free space (∆V) are lower than the ∆V of β-CL20 (∆V = 86). In view of the synthesis feasibility, the synthesis routes of HEDC-4, HEDC-9, HEDC-10, HEDC-12, HEDC-13, and HEDC-14 have been designed.

New potential high energy density compounds: Oxadiaziridine derivatives

The -CN, -N3, -NF2, -NH2, -NHNO2, -NO2, and -ONO2 derivatives of oxadiaziridine were studied using B3LYP/6-311G** level of density functional theory. The gas phase heats of formation of oxadiaziridine derivatives were calculated by isodesmic reaction. All these compounds have high and positive heats of formation due to strain energies of small ring. Detonation properties were calculated via Kamlet-Jacobes equations and specific impulse. The effects of substituent groups on detonation performance were discussed. The impact sensitivity was estimated according to the “available free space per molecule in unit cell” and “energy gaps” methods. The similar conclusions were given by two different methods. The effects of substituents on impact sensitivity were discussed. According to the given estimations of detonation performance and sensitivity, some oxadiaziridine derivatives may be considered promising high energies materials.

Dinitroamino benzene derivatives: a class new potential high energy density compounds

Dinitroamino benzene derivatives are designed and studied in detail with quantum chemistry method. The molecular theory density, heats of formation, bond dissociation energies, impact sensitive and detonation performance are investigated at DFT-B3LYP/6-311G** level. The results of detonation performance indicated most of the compounds have better detonation velocity and pressure than RDX and HMX. The N-N bond can be regard as the trigger bond in explosive reaction, and the bond dissociation energies of trigger bond are almost not affected by the position and number of substituent group. The impact sensitive are calculated by two different theory methods. It is found that the compounds, which can become candidates of high energy materials, have smaller H50 values than RDX and HMX. It is hoped that this work can provide some basis information for further theory and experiment studies of benzene derivatives.

Theoretical studies on a series of 1,2,4-triazoles derivatives as potential high energy density compounds

Density functional theory calculations at B3LYP/6-31G** and B3P86/6-31G** levels were performed to predict the densities (ρ), detonation velocities (D), pressures (P) and the thermal stabilities for a series of 1,2,4-triazole derivatives for looking high energy density compounds (HEDCs). The heats of formation (HOFs) are also calculated via designed isodesmic reactions. The calculations on the bond dissociation energies (BDEs) indicate that the position of the subsitutent group has great effect on the BDE and the BDEs of the initial scission step are between 31 and 65 kcal/mol. In addition, the condensed phase heats of formation are also calculated for the title compounds. These results would provide basic information for further studies of HEDCs. Densities, detonation velocities and pressures for a series of 1,2,4-triazole derivatives, as well as their thermal stabilities, were investigated to look for high energy density compounds (HEDCs). Heats of formation (HOFs) were also calculated via designed isodesmic reactions. 5,5′-Dinitro-3,3′-bi-1,2,4-triazole, 3-nitro-1-picryl-1,2,4-triazole and 4-(2,4-dinitrobenzyl)-3,5-dinitro-1,2,4-triazole satisfy the quantitative standard of HEDC.

ChemInform Abstract: Density Functional Theoretical Study of Polynitrogen Compounds N5+Y‐ (Y: B(CF3)4, BF4, PF6 and B(N3)4).

The structures and the stabilities of polynitrogen compounds N5+Y− [Y=B(CF3)4, BF4, PF6, and B(N3)4], as the potential high energy density compounds, have been investigated at the B3LYP/6-31G(d,p) and B3LYP/6-311+G(d,p) levels. On the basis of our geometry optimization calculations, the structural properties of the N5+Y− compounds are discussed, and it is found that the combination of the N5+ cation and the Y− anions leads to distortion of the structures of the Y− anions. Based on the TS calculations for the N2-loss dissociations of the N5+Y− compounds, the stabilities of these compounds are discussed, and the following conclusion can be drawn that among the four compounds, N5+B(CF3)4− is the most stable one and N5+B(N3)4− is the most unstable, and the relative stability of these compounds is always consistent using different basis sets. From these discussions, it is revealed that there are close correlations between the stuctrual distortions of the Y? anions and the stabilities of the N5+Y− compounds, and between the nitrogen content in the compounds and the stabilities of the N5+Y− compounds.

Density Functional Theoretical Study of Polynitrogen Compounds N5+Y− (Y=B(CF3)4, BF4, PF6 and B(N3)4)

AbstractThe structures and the stabilities of polynitrogen compounds N5+Y− [Y=B(CF3)4, BF4, PF6, and B(N3)4], as the potential high energy density compounds, have been investigated at the B3LYP/6‐31G(d,p) and B3LYP/6‐311+G(d,p) levels. On the basis of our geometry optimization calculations, the structural properties of the N5+Y− compounds are discussed, and it is found that the combination of the N5+ cation and the Y− anions leads to distortion of the structures of the Y− anions. Based on the TS calculations for the N2‐loss dissociations of the N5+Y− compounds, the stabilities of these compounds are discussed, and the following conclusion can be drawn that among the four compounds, N5+B(CF3)4− is the most stable one and N5+B(N3)4− is the most unstable, and the relative stability of these compounds is always consistent using different basis sets. From these discussions, it is revealed that there are close correlations between the stuctrual distortions of the Y? anions and the stabilities of the N5+Y− compounds, and between the nitrogen content in the compounds and the stabilities of the N5+Y− compounds.

Computational DFT studies on a series of toluene derivatives as potential high energy density compounds

Based on the full optimized molecular geometric structures at B3LYP/6-31G**, B3LYP/6-31+G**, B3P86/6-31G**, and B3P86/6-31+G** levels, the densities (ρ), detonation velocities (D), and pressures (P) for a series of toluene derivatives, as well as their thermal stabilities, were investigated to look for high energy density compounds (HEDCs). The heats of formation (HOFs) are also calculated via designed isodesmic reactions. The calculations on the bond dissociation energies (BDEs) indicate that the BDEs of the initial scission step are between 48 and 59 kcal/mol, and pentanitrotoluene is the most reactive compound, while 2,4,6-trinitrotoluene is the least reactive compound for toluene derivatives studied. A good linear relationship between BDE/E and impact sensitivity is also obtained. The condensed phase HOFs are calculated for the title compounds. These results would provide basic information for the further studies of HEDCs. The detonation data of pentanitrotoluene show that it meets the requirement for HEDCs.

DFT Studies on Detonation Properties, Pyrolysis Mechanism, and Stability of the Nitro and Hydroxyl Derivatives of Benzene

AbstractNinety‐one nitro and hydroxyl derivatives of benzene were studied at the B3LYP/6‐31G∗︁ level of density functional theory. Detonation properties were calculated using the Kamlet‐Jacobs equation. Three candidates (pentanitrophenol, pentanitrobenzene, and hexanitrobenzene) were recommended as potential high energy density compounds for their perfect detonation performances and reasonable stability. The pyrolysis mechanism was studied by analyzing the bond dissociation energy (BDE) and the activation energy (Ea) of hydrogen transfer (H–T) reaction for those with adjacent nitro and hydroxyl groups. The results show that Ea is much lower than BDEs of all bonds, so when there are adjacent nitro and hydroxyl groups in a molecule, the stability of the compound will decrease and the pyrolysis will be initiated by the H–T process. Otherwise, the pyrolysis will start from the breaking of the weakest C–NO2 bond, and only under such condition, the Mulliken population or BDE of the C–NO2 bond can be used to assess the relative stability of the compound.